Holder for bits



2 Pfi 3. n 5 5, 2

May 8, 1951 H. M. MoRRow ET AL HOLDER FOR BITS 2 Sheets-Sheet 1.

Filed Dec. 16, 1944 INVENTOR.

y 1951 H. M. MORROW ET AL 5 9 HOLDER FOR BITS Filed DC. 16, 1944 v 2 Sheets-Sheet 2 Patented May 8, 1951 HOLDER FOR BITS Harry M. Morrow and Charles L. Bowman, Canton, Ohio, assignors to The Bowdil Company Application December 16, 1944, Serial No. 568,453

3 Claims. 1

Our invention relates in general to mining machine cutting chains and more particularly to a bit holder for a mining machine chain lug.

The mining machine chain in which this bit holding body is employed is the type consisting of an endless chain. Each of the several bits held in the chain block of the endless chain will cut its equal share only if all are maintained at a uniform distance or gauge from the chain lug. Further, the area surrounding the cutting bit is subjected to extensive wear because of its exposed position. It has been generally recognized that a suitable replaceable holder for the bit is desirable because it may be replaced at a lower cost than replacing the entire block. Many different types of holders have been used in the past, but generally it is necessary to remove the holder as well as the bit Whenever a bit is to be replaced or reversed. Although these holders receive a considerable amount of wear, they do not receive as much wear as the actual cutting bit, and therefore, have a much longer life than the bit. It is desirable, therefore, that a bit holder be used which is replaceable in the block, but which is disposed to release the bit without actually moving or unseating the holder from the block recess.

Therefore, an object of our invention is the provision of a replaceable bit holder for a bit carrying block which fits semi-permanently in a recess of the block and is disposed to release a bit therefrom without itself being disturbed.

Another object of our invention is the provision for holding a cutting bit at a uniform distance or gauge from the chain lug.

Another object of our invention is the provision for holding a bit within a recess of a chain lug block with a clearance between the butting face of the bit and the recess so as not to interfere with the proper gauging of the bit in the chain lug.

Another object of our invention is the provision of improved means to anchor a bit holder shank within the recess of a chain lug.

Another object of our invention is the provision. of a bit holder for holding a bit within the recess of a chain lug which permits insertion and withdrawal of the bit into the bit holder Without removing the bit holder from the recess.

Another object of our invention is the provision of a replaceable chain lug shield on the forward end of the chain lug to take the wear and preserve the chain lug.

Other objects and a fuller understanding of our invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawing, in which:

Figure 1 is a side-elevational view of a mining machine chain lug and block having a bit holder therein and embodying the features of our invention;

Figure 2 is a side-elevational view of the chain block illustrating the position of inner recess and bit holder surfaces in outline form;

Figure 3 is a top view of the Figure 2;

Figure 4 is a front end view of the Figure 2;

Figure 5 is a side-elevational view of a block employing a lock means having an extension to interlock with the bit holder, and hold the holder within the. recess of the block;

Figure 6 illustrates an alternative method of holding the bit holder within the block recess;

Figure 7 illustrates an alternative type of clamp means to clamp the bit within the bit holder;

Figure 8 is still another alternative means for clamping the bit holder within the recess of the chain block;

Figure 9 is a view of the Figure 8 taken along the lines 9-9 of Figure 8; and

Figure 10 is a cross-sectional view of the Figure 8 taken along the lines Ill-l0 of the Figure 8.

With reference to the drawings, a mining machine chain lug and block to carry a bit holder embodying the features of our invention may comprise a chain lug Ill having a block I l, a bit holder 52 for receiving a bit I3, a clamp l5, and a set screw i6 for securing the clamp against the bit :3 contained within a bit receiving socket l9 within the holder l2.

The cutting bit may be of any suitable type and is illustrated as a double ended or pointed type having a rhomboidal outline in side-elevation and having substantially diamond shape parallel end cutting faces ofif-set relative to each other at a rhomboidal angle.

With reference to the Figures 2 and 3 of the drawings, we illustrate an embodiment of a block and holder conforming to the features of our invention. In the Figure 2, we illustrate a block recess 3| having a slightly tapering form from the top to the bottom of the block. The bit holder !2 has a shank portion M with side walls fitting complementary within the recess 3|. The recess 3: and the shank I4 are preferably machined to give a taper to form a wedge-grip action therebetween. Tapers of this nature have been known in various arts ,for some period of time and are known by such names as, for example, Morse taper, or it may be stated that the walls of the recess and the shank taper in the order of .625 inch per foot of length. Thus, when the shank M its-placed in the recess 3| with a slight amount of force, the shank I4 is wedged tightly in place and is not easily removed. In

er I2 without interference.

the Figure 2, we illustrate a bit I3 of rhomboidal side-elevation fitting into a socket I9 in the bit holder I2. Thus, a cutting face 26 projects outwardly and forwardly from the recess socket I9 with the inactive portion 2| of the cutting face 20 disposed within the recess SI, and an active portion 22 of the cutting face 26 constituting an active cutting face of the bit I3. It is noted that an opening I8 is provided at the end of the socket l9 and communicates with the bottom of the shank portion I4 to allow any foreign material which might drop into the socket I9 to egress therefrom and not interfere with the holding of the bit I3.

A sloping race 32 with low side walls 33 and l 33 is provided on the block I I at an angle to the longitudinal axis of the recess 3I. The clamp is disposed to ride in the race 32 and is actuated relative to the bit It by means of a set screw I6. Although an oval recess may be provided for the shank l4, it is possible to provide a recess of circular cross-section with less effort and greater accuracy by machining. Therefore, in order to provide a clearance for the inactive portion 2| of the cutting .face 2% on the bit I3, a sloping notch .35 is provided at the upper edge of the recess 3I.

In operation, the bit holder I2 is placed with its shank portion I4 in the recess 3| of the block II and a bit I3 is placed in the bit receiving socket portion IQ of the bit holder I2. The

clamp I5 is then brought to bear against the.

portion 2! of the bit face 23 by means of the said set screw IS. The upper surface of the clamp I5 may be provided with a small notch 35 to fit partly around the bit I3.

It will be readily understood with reference to the Figure 2 of the drawing and the discussion in connection therewith, that the surfaces of the recess 3i and the shank portion It may be made with close accuracy by machining and v as a result the bit holder I2 will proceed a pre determined distance into the recess SI before it is arrested and brought to a stop. Also, a very tight wedge-grip action is produced. The provision of the notch allows the bit IE to rest in the bit receiving socket portion I 9 of the hold- The predetermined stopping place provision, in conjunction with the clearance permitted by the notch 35, produces a definite gauge in the bit It. That is, the active cutting portion 22 of the bit I3 will be placed a predetermined distance from the surface of the block II. Further, as long as the clamp I5 is not in place, a free path is provided whereby the bit I3 may be inserted or withdrawn from the socket I9 without interference. The bit I3 may be then made secure within the socket I9 by placing the clamp I5 securely in contact with the inactive cutting portion 2! of the bit I 3.

It will be understood that the block II and the bit holder and bit therein moves in a direction toward the set screw It When in operation. In other Words, the surface of the blocks II which is illustrated in the Figure 4 will receive the greatest amount of wear. Therefore, it is preferable that the clamp I5 be made of a very hard material, such for example, as heat treated steel which is extremely resistant to wear. This provision protects the main body I I from excessive wear and prolongs the life thereof.

With reference to the Figure 5, we illustrate an alternative method of anchoring the holder I2 within the recess 3|. In this illustration the clamp I5 is provided with extended clamp projections 29, which are disposed to fit into interlocking notch surfaces 30 of the holder I2. It will readily be understood that these interlocking surfaces between the projections 29 and the notches 30 will provide ample means to secure the holder I2 within the recess 3I. However, in order to assure an even gauge for the bit I3,

stop shoulders 23 are provided on the sides of the holder I2 and are disposed to contact the top surface of the block II. In this embodiment, as well as that illustrated in the Figure 2, when the holder I2 is in its stop arresting position with the stop means 23 in contact with the top of the lug II, a space 28 is provided between the Walls of the notches 3'5 and the surface of the bit I3 in order that a free path for insertion and withdrawal may be provided for the .bit I3, and that wedging between the surfaces may be prevented before the stop means is in position against the top surface of the block II.

Still another means for locking the bit holder I2 within the recess BI, is illustrated in the Figure 6. A set screw I1 is provided in this illustration, and is disposed to contact the straight shank I I of the holder I2 and clamp it in the recess 3!. All of the remaining features except the stop 23 are the same as those discussed and illustrated in connection with the Figure 2. The stop 23 limits the distance that the holder I2 progresses into the recess 3| in order to provide a definite gauge in the bit I3.

The Figure 7 illustrates an alternative type of clamp means to be used in place of the clamp I5 of the Figure .2. This clamp 33 is positioned within a clamp race having high side walls of which the wall 33 is illustrated. This clamp 38 .does not extend to the outer extremities of the body II, but is housed completely within the walls of the race. A split 31 is provided in the clamp '38 to serve as a lock means to prevent the set screw I8 from becoming loosened during service. All other features of this embodiment are similar to those discussed in connection with Figure 2.

The Figure 8 illustrates another alternative method. of securing the holder I2 within the recess 3i. In the Figures 8, 9 and 10, we illustrate a rod 24 extending from one side of the body II to the other side of the body I I and with a surface thereof projecting into the recess 3|. This method of providing a projecting surface within the recess 3I is employed because of its simplicity of construction. It is understood that an suitable projecting surface within the recess .11 maybe provided. The shank I3 of the holder I2 is provided with two flat surfaces positioned at a radial angle of in relation to one another. The first flat surface 26 is positioned at the extreme end of the shank It. The second flat surface 21, which is at a 90 angle to the first surface 26, is positioned a distance away from the end of the shank I l with its lowermost portion laterally opposite the top of the flat surface 25. A lateral groove 25 is provided to connect the top of the surface 26 with the bottom of the surface 2'1. To insert the holder I2, when equipped with this bayonet type anchoring means, the holder I2 is inserted with its flat surface 26 registering with the portion of the rod 24 that fits into the recess 3|. The holder I2 is then passed down until the rod 24 is at the top of the surface 26. The holder I2 is then rotated with the rod 24 registering with the groove 25 until the flat surface 21 is brought into position with the portion of the rod 24 projecting into the groove. The holder i2 is then free to drop down until stopped by suitable stop means. This bayonet type anchoring means may be used in conjunction with stops of the type illustrated by the reference character 3 in the Figures 5 and 6. All other features of this embodiment of my invention are similar to the features discussed and illustrated in connection with the Figure 2.

Although we have described our with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

We claim as our invention:

1. A chain lug bl ck having walls defining a recess socket extending downwardly from the top thereof, a bit and a bit holder receivable within said socket, means for removably holding said bit holder within said recess socket, said holder maintaining said bit in a cutting position out of supporting contact with said walls of the recess socket with a portion of the cutting face of the bit disposed within the recess and a portion thereof extending therefrom and constituting an active cutting face of the said bit, said holder and bit therein being bodily movable as a unit in a path axially of the socket into and out of said recess socket, said bit being separately movable into and out of the recess socket and into and out of the bit holder along a path at an angle to the axis of the recess socket, said chain lug block having an outside front wall surface extending upwardly at an angle to the axis of said recess socket, a rigid clamp block mounted on said front wall surface and being movable between a blocking position which permits the removal of the bit and holder as a unit axially of the recess socket but prevents the bit from being removed from the holder, and a second position which permits the bit to be removed from said holder, said holder and bit thereby being movable as a unit from the recess regardless of the position of the clamp block but said bit being removable from said holder while the holder is in said recess socket only when said clamp block is in said second position, and means to hold said clamp block member tightly secured to said front wall surface in said blocking position.

2. A chain lug block having walls defining a recess socket extending downwardly from the top thereof, a bit and a bit holder receivable within said socket, said bit holder having a shank portion, said shank portion and said recess having complementary tapering walls forming a wedge grip action therebetween to removably hold said shank portion in a substantially fixed position within said recess socket, said holder maintaining a bit in a cutting position out of supporting contact with said walls of the recess socket with a portion of the cutting face of the bit disposed within the recess and a portion thereof extending therefrom and constituting an active cutting face of said bit, said holder and bit therein being bodily movable as a unit in a path axially of the socket into and out of said recess socket, said bit being separately movable into and out of the recess socket and into and out of the bit holder along a path at an angle to the axis of the recess socket, said chain lug block having an outside front wall surface extending upwardly at an angle invention 1 to the axis of said recess socket, a rigid clamp block mounted on said front wall surface and being movable between a blocking position which permits the removal of the bit and holder as a unit axially of the recess socket but prevents the bit from being removed from the holder, and a second position which permits the bit to be removed from said holder, said holder and bit thereby being movable as a unit from the recess regardless of the position of the clamp block but said bit being removable from said holder while the holder is in said recess socket only when said clamp block is in said second position, and means to hold said clamp block member tightly secured to said front wall surface in said blocking position.

3. A chain lug block having walls defining a recess socket extending downwardly from the top thereof, a bit and a bit holder receivable within said socket, means for removably holding said bit holder within said recess socket, said holder maintaining said bit in a cutting position out of supporting contact with said walls of the recess socket with a portion of the cutting face of the bit disposed within the recess and a portion thereof extending therefrom and constituting an active cutting face of the said bit, said holder and bit therein being bodily movable as a unit in a path axially of the socket into and out of said recess socket, said bit being separately movable into and out of the recess socket and into and out of the bit holder along a path at an angle to the axis of the recess socket, said chain lug block having an outside front wall surface and side r walls defining a clamp race slot extending upwardly at an angle to the axis of said recess socket, a rigid clamp block mounted on said front wall surface and being movable between a blocking position which permits the removal of the bit and holder as a unit axially of the recess socket but prevents the bit from being removed from the holder, and a second position which permits the bit to be removed from said holder, said holder and bit thereby being movable as a unit from the recess regardless of the position of the clamp block but said bit being removable from said holder while the holder is in said recess socket only when said clamp block is in said second position, and means to hold said clamp block member tightly secured to said front wall surface in said blocking position.

HARRY M. MORROW.

CHARLES L. BOWMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 837,246 Noble Nov. 27, 1906 1,677,950 Bowman July 24, 1928 1,902,420 Radius Mar. 21, 1933 1,903,771 Bowman Apr. 18, 1933 1,908,161 Meutsch May 9, 1933 1,953,399 Stenger et al Apr. 3, 1934 2,103,509 Bowman Dec. 28, 1937 2,123,213 Simmons July 12, 1938 2,148,309 Stephens Feb. 21, 1939 2,156,726 Fulke May 2, 1939 2,254,747 McCullough Sept. 2, 1941 2,255,856 Morrow Sept. 16, 1941 2,263,590 Osgood Nov. 25, 1941 2,322,929 Fulke June 29, 1943 2,434,256 Bowman Jan. 13, 1948 

